Rheinmetall and Steyr Mannlicher, have joined forces to manufacture and market the RS556 modular assault rifle based on STM556, which Steyr Mannlicher first unveiled in 2012. The German-Austrian partnership has its sight set on the German market. This innovative weapon is a possible candidate for the new "System Sturmgewehr Bundeswehr": The German armed forces intend to replace their standard G36 assault rifle with a more advanced system starting in 2019, Rheinmetall said in a statement Wednesday.

The weapon is being offered by Rheinmetall and Steyr Mannlicher as a jointly produced product, made in Germany, with a German valued added share of 60%.

Featuring an adjustable short-stroke gas piston system and rotating bolt, the gas-operated RS556 is based on the Steyr Mannlicher AUG, a design concept.

With a 16" barrel (406 mm) and a fully loaded, 30-round magazine, the RS556 weighs around 4.2 kilograms, just over 9 pounds. The adjustable-length light-weight stock clicks into seven different positions, meaning that operators can adjust the RS556 to match their individual equipment profile in optimum fashion.

In a matter of seconds and without tools, the hammer-forged barrel can be easily exchanged. A number of standard barrel lengths are available (14.5", 16", 18" and 20"); however, customer-specific barrel and rifling lengths can be easily created.

The RS556 features several standard and optional NATO accessory rails with receiver systems designed in accordance with MIL-STD-1913, STANAG 2324 and STANAG 4694. This means that the weapon can be fitted with various optics and night observation devices or laser light modules.

A 40mm grenade launcher can also be mounted on the new assault rifle. Moreover, the RS556 is compatible with Rheinmetall’s modular "Future Soldier - Expanded System" (IdZ-ES), and can also be connected to other soldier systems.

A special breech system with an emergency operation feature ensures that the weapon always functions reliably even in extreme operating conditions, e.g. in severely hot and cold environments.